1. Technical Field
The present disclosure relates to methods and apparatuses for finding out a generation point of a passive intermodulation (PIM), and more particularly, to methods and apparatuses for rapidly and correctly finding out a generation point of PIM.
2. Related Art
According to the current increase of demands for mobile networks and wireless data services, foreign or domestic mobile communication operators make efforts to secure more frequency bands and construct efficient mobile networks enabling multi-band services. Due to the high construction cost and maintenance cost, it's not practically easy to install and operate respective in-building feeders for multiple frequency bands. Thus, cases using a common in-building feeder to provide services through various frequency bands are increasing currently.
However, in the case that a common feeder is used to provide multi-band services in a building, a passive intermodulation (PIM) may occur, thereby causing interferences between upward channel and downward channel, and thus reducing a service range and deteriorating telephone connection efficiencies. Since the PIM may occur due to contact inferiority caused by deterioration of passive elements such as cable connectors, multiplexers, and circulators, the disfunctional elements should be replaced or repaired in order to solve the problem of PIM. Also, since the in-building feeders are laid in the ceiling or wall, a PIM generation point should be correctly estimated in order to promptly replace or repair the disfunctional elements.
For this, conventional PIM generation point detection apparatuses estimate a PIM generation point approximately by determining, through a digital signal processing, a beat frequency according to a time delay between a reference signal generated utilizing a Frequency Modulation Continuous Wave (FMCW) signal and a Continuous Wave (CW) signal, and a PIM signal returned after being inputted to an input end of the in-building feeder. However, since the conventional PIM generation point detection apparatuses have accuracy of several meters, several candidate PIM generation points may be estimated, whereby the replacement or repair of the disfunctional elements take too much time.